<template>
  <div class="home">
    <p>
      <label>Pattern left offset</label>
      <input type="range" min="0" max="500" value="0" id="img-offset-x">
    </p>
    <canvas id="canvas" width="1565" height="929"></canvas>
  </div>
</template>

<script setup>
import {onMounted} from "vue";

let canvas, rect, patternSourceCanvas, pattern;

fabric.Sprite = fabric.util.createClass(fabric.Image, {

  type: 'sprite',

  spriteWidth:  50,
  spriteHeight: 72,
  spriteIndex: 0,
  frameTime: 100,

  initialize: function(element, options) {
    options || (options = { });

    options.width = this.spriteWidth;
    options.height = this.spriteHeight;

    this.callSuper('initialize', element, options);

    this.createTmpCanvas();
    this.createSpriteImages();
  },

  createTmpCanvas: function() {
    this.tmpCanvasEl = fabric.util.createCanvasElement();
    this.tmpCanvasEl.width = this.spriteWidth || this.width;
    this.tmpCanvasEl.height = this.spriteHeight || this.height;
  },

  createSpriteImages: function() {
    this.spriteImages = [ ];

    var steps = this._element.width / this.spriteWidth;
    for (var i = 0; i < steps; i++) {
      this.createSpriteImage(i);
    }
  },

  createSpriteImage: function(i) {
    var tmpCtx = this.tmpCanvasEl.getContext('2d');
    tmpCtx.clearRect(0, 0, this.tmpCanvasEl.width, this.tmpCanvasEl.height);
    tmpCtx.drawImage(this._element, -i * this.spriteWidth, 0);

    var dataURL = this.tmpCanvasEl.toDataURL('image/png');
    var tmpImg = fabric.util.createImage();

    tmpImg.src = dataURL;

    this.spriteImages.push(tmpImg);
  },

  _render: function(ctx) {
    ctx.drawImage(
        this.spriteImages[this.spriteIndex],
        -this.width / 2,
        -this.height / 2
    );
  },

  play: function() {
    var _this = this;
    this.animInterval = setInterval(function() {

      _this.onPlay && _this.onPlay();
      _this.dirty = true;
      _this.spriteIndex++;
      if (_this.spriteIndex === _this.spriteImages.length) {
        _this.spriteIndex = 0;
      }
    }, this.frameTime);
  },

  stop: function() {
    clearInterval(this.animInterval);
  }
});

fabric.Sprite.fromURL = function(url, callback, imgOptions) {
  fabric.util.loadImage(url, function(img) {
    callback(new fabric.Sprite(img, imgOptions));
  });
};

fabric.Sprite.async = true;

function init() {
   canvas = new fabric.Canvas('canvas');
   rect = new fabric.Rect({
    top: 100,
    left: 100,
    width: 1565,
    height: 50, objectCaching: false,
  });
  canvas.add(rect);
  fabric.Image.fromURL('/img/road2.jpg', function(oImg) {
    patternSourceCanvas = new fabric.StaticCanvas();
    patternSourceCanvas.add(oImg);
    patternSourceCanvas.renderAll();
    pattern = new fabric.Pattern({
      source: patternSourceCanvas.getElement(),
      repeat: 'repeat',
    });
    rect.set('fill', pattern);
    canvas.requestRenderAll();
    document.getElementById('img-offset-x').oninput = function () {
      pattern.offsetX = parseInt(this.value, 10);
      console.log(pattern.offsetX)
      canvas.requestRenderAll();
    };
  })

  let createSprite = () => {
    return function(sprite) {
      sprite.set({
        left: 500,
        top: 500,
      });
      canvas.add(sprite);
      sprite.scale(4).setCoords();
      canvas.requestRenderAll();
      setTimeout(function() {
        sprite.set('dirty', true);
        sprite.play();
      }, fabric.util.getRandomInt(1, 10) * 100);
    };
  }

  fabric.Sprite.fromURL('/img/fire.png', createSprite(), {
    spriteWidth: 1200/15,
    spriteHeight: 85,
  });

}



function animal () {
  if (pattern && patternSourceCanvas)
  {
    pattern.offsetX = pattern.offsetX + 2;
    canvas.requestRenderAll();
  }
  requestAnimationFrame(animal)
}

onMounted(() => {
   init()
   animal()
})

</script>

<style lang="less">
.home {
  height: 100%;
}
</style>
